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. 2015 May 11;10(5):e0124814. doi: 10.1371/journal.pone.0124814

Table 1. Efflux pump inhibitory activity and antimicrobial activity of flavonoids.

Flavonoid IC50 for efflux inhibition a MIC b
Apigenin 38 μg/mL (140 μM) >150 μg/mL (>560 μM)
Kaempferol 19 μg/mL (66.0 μM) >150 μg/mL (>520 μM)
Rhamnetin 19 μg/mL (60.0 μM) >150 μg/mL (>470 μM)
Quercetin 75 μg/mL (250 μM) >150 μg/mL (>500 μM)
Luteolin 75 μg/mL (260 μM) 75 μg/mL (260 μM)
Myricetin 75 μg/mL (240 μM) 150 μg/mL (470 μM)
CCCP c 4.7 μg/mL (23 μM) 0.29 μg/mL (1.4 μM)

a: Efflux pump inhibition was measured via LC-MS analysis of ethidium in spent, filtered culture supernatant after a 30 min incubation in triplicate wells.

b: Growth inhibition was measured by optical density at 600nm (in triplicate) after an 18 hr incubation.

c: CCCP is an abbreviation for the compound carbonyl cyanide m-chloro-phenylhydrazone